And across this country here at home today, people were weighing in about the supreme court ruling on money and politics. The court striking down a limit on campaign contributions. And raising new questions about the influence of millionaires and billionaires, in the races for congress and the white house. Tonight, ABC's chief investigative correspondent, Brian Ross, is back on the money trail. Reporter: The real campaign in American politics begins long before and far away from the confetti and balloons and speeches. The real campaign for both parties takes place at fancy dinners and luxury yachts. What's your name? Can't say your name? No. Reporter: Where the super rich decide which politicians get their money, and therefore who has a chance to be elected. Without it, you're pretty much dead in the water. Reporter: With this week's supreme court ruling, finding spending limits invalid, reach donors can give to every member in congress, leaving average Americans on the sideline. Your voice is going to be drowned out by the massive contributions from a few wealthy, interested parties. Reporter: Indeed, a handful of billionaires from Las Vegas to Wall Street have emerged as the country's backroom power brokers. On the republican side, there's been a parade of potential presidential candidates to see casino owner Sheldon Adelson, who says he is prepared to spend $100 million if he can find the right candidate. And the secretive David Koch, along with his brother, Charles, are also good for close to $100 million for the candidates who they say support core American values. Democrats portray the kochs, as evil. These two men are a pair of shadow billionaires, spending millions of dollars to rig our political system. Reporter: But the democrats have their own big money figures. California billionaire and environmental activist Tom Steyer has put out the word he, too, will put out $100 million dollars for the coming elections cycle. And the son of billionaire George Soros, Jonathan, is promising to use his own money and access, ironically, to push for reforms that would undercut the role of big money and access in politics. Are you using the system like those who are often criticized for it? Yes, absolutely. I'm not going to pretend we are not. Reporter: Soros was the only one of the big-money players to agree to appear in our report tonight. Of course, he's the one who is trying to end a system that many, including republicans and democrats, believe have made American politics a private playground for the rich. Diane? Brian Ross, reporting in. Thank you, Brian.

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